Skype was absolutely awful for many years. I'm trying to remember all the things that were bad, but I remember that they reinvented the app twice, so that everyone could only talk to people on the version of the app they were on.

They left Linux users in limbo, while Zoom worked for everyone.

They couldn't handle more than a couple of people in a call.

They also had Lync which was rebranded as Skype, so you also had other bad software masquerading as Skype which wouldn't have helped their image.

You couldn't share a meeting URL and have the call in a browser for the longest time.

They only started to try again after Zoom picked up being the default word for video calls.